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Publication numberUS4413089 A
Publication typeGrant
Application numberUS 06/356,717
Publication dateNov 1, 1983
Filing dateMar 10, 1982
Priority dateMar 10, 1982
Fee statusPaid
Also published asCA1218493A1, DE3375149D1, EP0088633A1, EP0088633B1
Publication number06356717, 356717, US 4413089 A, US 4413089A, US-A-4413089, US4413089 A, US4413089A
InventorsFrancis M. Gavin, Anne M. Kruglewicz
Original AssigneeE. I. Du Pont De Nemours And Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Alumina trihydrate filler
US 4413089 A
Abstract
A dispersion of iron oxide pigments, selected according to particle size to avoid interference with desired properties is added to a polymerizable acrylic composition containing alumina trihydrate as filler. This mixture is cured to form a filled polymeric structure containing 15 to 80% by weight polymethyl methacrylate and 20 to 85% by weight alumina trihydrate with a pleasing uniform color, maintaining desired properties of machinability, translucency, and visual depth.
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Claims(1)
What is claimed is:
1. In a process for preparing a filled polymethyl methacrylate article, said article consisting essentially of 20 to 85% by weight alumina trihydrate and 15 to 80% by weight polymethyl methacrylate and having properties of translucency and an appearance of visual depth, said process comprising curing a polymerizable composition consisting essentially of polymerizable methyl methacrylate and alumina trihydrate, the improvement whereby a dispersion of iron oxide pigments having a particle size of 10 microns or less is prepared and blended thoroughly with said polymerizable composition prior to curing, whereby upon curing said article has properties of uniform color in addition to maintaining said properties of translucency and an appearance of visual depth.
Description
BACKGROUND OF THE INVENTION

The invention relates to filled polymeric compositions formed into cast slabs, sheets, and article useful in the building arts, more particularly to polymethyl methacrylate compositions containing alumina trihydrate filler useful for construction details and applications such as kitchen counter tops and back splash panels, bathroom vanity tops and bowls, and other molded articles such as towel racks.

DESCRIPTION OF THE PRIOR ART

The preparation of filled acrylic articles utilizing alumina trihydrate as a multifunctional filler is disclosed in U.S. Pat. No. 3,847,865 issued to Ray B. Duggins on Nov. 12, 1974. The preferred polymer constituent of the filled polymeric article disclosed therein comprises a methyl methacrylate polymer including homopolymers and copolymers of methyl methacrylate with other ethylenically unsaturated compounds (e.g., vinyl acetate, styrene, alkyl acrylates, acrylonitrile, alkyl methacrylate, multifunctional acrylic monomers such as alkylene dimethacrylates and alkylene diacrylates). In addition, the polymer constituent can contain small amounts of other polymers including minor amounts of polyester. The resulting filled polymeric structure in Duggins, comprising 20 to 85%, preferably 55 to 80%, by weight of the structure, alumina trihydrate, and 15 to 80%, preferably 20 to 45%, polymethyl methacrylate, has an important combination of properties including translucency, weather resistance, resistance to staining by common household materials, and resistance to stress cracking. In addition, the cured structure can be easily machined by conventional techniques including sawing and sanding. This particular combination of properties makes such a structure particularly useful as kitchen or bathroom counter tops. Duggins discloses the preparation of a preferred polymerizable acrylic composition consisting essentially of a syrup containing methyl methacrylate polymer dissolved in monomeric methyl methacrylate (polymer-in-monomer syrup), a polymerization initiator, and alumina trihydrate. This polymerizable composition can be cast or molded and cured to produce a structure with the desired combination of properties given above.

It has been known to produce the filled polymethyl methacrylate structures in pleasing commercially reproducible, variegated patterns which closely approximate the appearance of natural stone such as marble and granite. The above referenced patent to Duggins, U.S. Pat. No. 4,159,301 issued to Kenneth Rene Buser et al. on June 26, 1979, and U.S. Pat. No. 3,706,825 issued to Nelson Lee Hall et al. provide examples of such patterns.

The property of translucency obtained in a polymethyl methacrylate structure containing alumina trihydrate as filler has proven to be a valuable property which greatly enhances the appearance of visual depth in the resulting structure. This appearance of visual depth is aesthetically pleasing and adds to consumer appeal for the structure as a kitchen or bathroom countertop, for example.

Until the present invention, however, there has been no method of producing a filled polymethyl methacrylate structure with a pleasing uniform color or hue other than white. To meet desires of consumers, of course, it is preferable to have a choice of colors. Attempts to pigment the acrylic structure created problems in that the pigmentation created an undesired level of masking which interfered with the aesthetically desirable translucency and visual depth properties of the cured structure. Additionally, in many instances the pigmented structures would "scratch white", i.e. scratches in the surface of the pigmented structure would appear white in contrast, and subsequent sanding to remove the scratches would lessen the intensity of the color rather than returning the surface to a uniform color.

SUMMARY OF THE INVENTION

A filled polymethyl methacrylate structure, with alumina trihydrate as filler, has a pleasing, uniform color obtained from iron oxide pigmentation, with no diminution in desired properties of machinablility, translucency, and visual depth. The process of obtaining this structure includes adding a dispersion of certain iron oxide pigments to a polymerizable acrylic composition, then curing to form the filled polymethyl methacrylate article of the desired uniform color. The polymerizable acrylic composition containing iron oxide pigments is also claimed.

DETAILED DESCRIPTION OF THE INVENTION

It has been found that by preparing a dispersion of iron oxide pigments, adding this dispersion to a polymerizable acrylic composition containing alumina trihydrate as filler, casting or molding this composition, then curing to form a filled polymethyl methacrylate article, there is obtained a structure with a pleasing, uniform color which has desired properties of machinability, translucency, and appearance of visual depth.

Selection of iron oxide pigments is of course important to the realization of the final color of the finished polymethyl methacrylate structure. This choice can be determined by one skilled in the art depending on the final color desired. Of essential importance to the invention herein, iron oxide pigments of a sufficiently small particle size must be selected in order to obtain a structure with desired properties. Iron oxide pigments of a smaller particle size avoid undesired masking of the translucency and visual depth desired in the finished article. Preferred iron oxide pigments have a particle size of 10 microns or less.

The iron oxide pigments must be well dispersed in a stable dispersion before addition to the polymerizable acrylic composition. The vehicle chosen for making the pigment dispersion must be carefully chosen to avoid any interference with the polymerization of the acrylic composition. The pigments can be dispersed in a polymerizable methyl methacrylate vehicle similar to that contained in the polymerizable acrylic composition, though this would lead to shelf-life problems with the pigment dispersion. If it is contemplated that the pigment dispersion would be stored for any period before addition to the polymerizable acrylic composition, it is better to select a dispersant medium that will be compatible with the acrylic composition and will not interfere with the polymerization reaction.

A preferred polymerizable acrylic composition disclosed in the above referenced patent to Duggins consists essentially of a syrup containing methyl methacrylate polymer dissolved in monomeric methyl methacrylate (polymer-in-monomer syrup), a polymerization initiator, and alumina trihydrate as filler. A measured amount of iron oxide pigment well dispersed in a suitable dispersant, for example a soybean oil epoxide resin, is mixed with the preferred acrylic composition consisting essentially of methyl methacrylate polymer-in-monomer syrup and alumina trihydrate. The resulting mixture is blended thoroughly, then cast or molded in ways known to the art, and cured to form a filled polymethyl methacrylate article of a desired uniform color, maintaining desired aesthetic properties of translucency and visual depth.

It is understood that the degree of translucency in the finished product can be adjusted to a desired level through variations in the acrylic composition. For example, inert fillers such as calcium carbonate or silicon dioxide can be used along with the alumina trihydrate additive. If desired, for example in a thin sheet of finished polymeric material, opaqueness can be achieved by the inclusion of sufficient masking pigment such as TiO2 in the pigment dispersion.

EXAMPLE I

A dispersion of iron oxide pigments in soybean oil epoxide resin was prepared using the following formulation, amounts given in weight %:

48.66% soybean oil epoxide resin

42.23% fine yellow pigment, a ferric hydroxide pigment containing approximately 82.5% Fe2 O3

9.11% black iron oxide pigment containing 98% Fe3 O4

A polymerizable acrylic composition consisting essentially of 60% by weight alumina trihydrate and 40% by weight methyl methacrylate polymer-in-monomer syrup was prepared in accordance with the above referenced patent to Duggins. To this composition was added 0.003 weight% of the iron oxide pigment dispersion. The mixture was blended thoroughly, then poured into a container to form a layer of approximately 1/2" thickness and allowed to cure. The resulting filled polymethyl methacrylate article had a uniform almond color, with acceptable levels of translucency and appearance of visual depth.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3706825 *Jun 9, 1970Dec 19, 1972Du PontProcess for manufacture of an improved multi-colored plastic building product
US3780156 *Apr 3, 1972Dec 18, 1973Du PontProcess for making filled methyl methacrylate articles
US3827933 *Apr 3, 1972Aug 6, 1974Du PontFilled polymethyl methacrylate article and a process for its manufacture
US3847865 *Sep 26, 1973Nov 12, 1974Du PontUse of alumina trihydrate in a polymethyl methacrylate article
US4085246 *Jun 18, 1975Apr 18, 1978E. I. Du Pont De Nemours And CompanyPolymer, microscopic filler, macroscopic opaque particles, macrospopic translucent and/or transparent particles
US4145477 *Nov 11, 1974Mar 20, 1979Rohm And Haas CompanyCrosslinking acrylic polymer dissolved in acrylic monomer
US4159301 *Feb 2, 1978Jun 26, 1979E. I. Du Pont De Nemours And CompanySimulated granite and its preparation
US4183991 *May 2, 1977Jan 15, 1980Rohm And Haas CompanyProcess for preparing highly filled acrylic articles
US4185070 *Nov 10, 1977Jan 22, 1980Union Carbide CorporationAlumina trihydrate
FR2342948A1 * Title not available
Non-Patent Citations
Reference
1 *Derwent Abst. 1D113 D/07 BASF (Jan. 1981) (DS2941807).
2 *Derwent Abst. 42683 D/24 Mitsubishi Rayon (4-1981) (J56043302).
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4643921 *Jul 26, 1985Feb 17, 1987Inax CorporationSimulated marble article
US4771095 *Jul 16, 1987Sep 13, 1988Dynamit Nobel AgAluminum hydroxide filled casting resins on a basis of methacrylic acid esters, and plastic objects and moldings manufactured therefrom
US5073587 *Jan 16, 1990Dec 17, 1991Edwards Bill RPolymeric composition and method of producing same
US5094057 *Jan 16, 1990Mar 10, 1992Morris Phillip LAnchor for simulated marble panels and the like
US5145903 *Mar 29, 1990Sep 8, 1992Imperial Chemical Industries PlcAcrylic composite materials
US5286290 *Apr 16, 1992Feb 15, 1994Avonite, Inc.Dehydration of aluminum trihydrate; rehydration with a dye solution; uniform coloring throughout; distribution in resin matrix to make solid decorative materials
US5344902 *Nov 30, 1992Sep 6, 1994Occidental Research CorporationPolymerization with initiator and quaternary ammonium salt
US5444115 *Nov 21, 1994Aug 22, 1995E. I. Du Pont De Nemours And CompanyFire resistant poly(methyl methacrylate) composition
US6177499 *Mar 10, 1999Jan 23, 2001Aristech Acrylics LlcCrosslinked polymethylmethacrylate (?pmma?), of the type usable in or designed for architectural uses
US6515060Feb 27, 2001Feb 4, 2003E. I. Du Pont De Nemours And CompanyHighly filled: acrylic resin, filler and synthetic fluorophlogopite; excellent physical properties and a lustrous, sparkling appearance
US6562927Jun 8, 2000May 13, 2003Aristech Acrylics LlcMethod of making a thermoformable article having uniform distribution of coloring and mineral filler before and after thermoforming
US7001660Aug 27, 2001Feb 21, 2006Gilbert GaritanoImages in solids surfaces
US8002929Oct 9, 2008Aug 23, 2011Images In Solid Surfaces, LlcImages in solid surfaces
US8679622Jul 20, 2006Mar 25, 2014Blanco Gmbh + Co KgCasting mass, in particular, for the production of kitchen sinks, molded sanitary articles, kitchen worktops or the like
US20110118402 *Jan 25, 2011May 19, 2011Cheil Industries Inc.Composite Solid Surface Article Containing Ocher
EP0497968A1 *Jun 24, 1991Aug 12, 1992Aristech Chemical CorporationAcrylic-filled thermoformable acrylic sheet
WO1996026238A1 *Feb 5, 1996Aug 29, 1996Aristech Chemical CorpAcrylic sheet having uniform distribution of coloring and mineral filler before and after thermoforming
WO2005071000A1 *Jan 21, 2005Aug 4, 2005Blanco Gmbh & Co KgCasting mass in particular for the production of kitchen sinks, moulded sanitaryware, kitchen worktops or similar
Classifications
U.S. Classification524/785, 524/437, 524/853, 524/435, 524/786, 524/560
International ClassificationC08F290/00, C08F20/00, C08F299/00, C08F2/44, C08L33/12, C08F20/14, C08L33/00, C08L33/04, C08L33/02, C08K3/22
Cooperative ClassificationC08F2/44, C08F20/14
European ClassificationC08F20/14, C08F2/44
Legal Events
DateCodeEventDescription
Apr 27, 1995FPAYFee payment
Year of fee payment: 12
Apr 25, 1991FPAYFee payment
Year of fee payment: 8
Mar 17, 1987FPAYFee payment
Year of fee payment: 4
Jun 1, 1982ASAssignment
Owner name: E.I. DU PONT DE NEMOURS AND COMPANY, WILMINGTON, D
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:GAVIN, FRANCIS M.;KRUGLEWICZ, ANNE M.;REEL/FRAME:003994/0900
Effective date: 19820304
Owner name: E.I. DU PONT DE NEMOURS AND COMPANY, WILMINGTON, D
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:GAVIN, FRANCIS M.;KRUGLEWICZ, ANNE M.;REEL/FRAME:003994/0898
Effective date: 19820305